On his forehead, Dash felt a trickle of sweat trickle down his forehead.

‘You see,’ said Colonel Daringman, handling his LaserBlasterGun carefully in his hand with care, ‘I knew that the only way to destroy you was through your sense of duty. Your sense of adventure. Your lack of a sense of where the sensible limits of risk are.’

‘So you sent me on a suicide mission?’ Dash growled with a growl.

‘Not quite,’ the Colonel frowned. ‘I knew you would never commit suicide on a suicide mission, so I sent you on a killing-you-with-a-dangerous-mission mission.’

‘You fiend!’ shrieked Samantha, fainting. ‘How could you?’

‘Let me show you,’ Daringman hissed with a hiss, stepping over the unconscious beauty. Dash felt the air around grow thick with the slowing of time as time seemed to slow. In that one fatal instant, he could see the energy beam emerging from the muzzle of the LaserBlasterGun as if it was space-ketchup coming out of a space-bottle. In actual fact, he knew it was moving at the speed of light or faster as it crawled through the air towards him like a baby made of deadly laser energy being fired from a gun. He was powerless to move, powerless to cry out or even to think. Time slowed again. The closer his death came – the laser baby dawdling now – the slower time seemed to get. In the last instant, the one that seemed to go on forever, he felt a sensation like a weight being lifted from him. For an infinite moment, he knew everything. Then, Dash Gallant, Captain of the Star Corps, hero of the battle of Tor’Sang, the only man ever to escape a Mhal-Evol’Unt interrogation unit, closed his eyes for the last time and joined the ranks of the dead.

Triple agents are old hat. In the Illuminatus! Trilogy, the ur-work of conspiracy fiction, one character is a quintuple agent, as he works simultaneously for the FBI, the CIA, the KGB, the Illuminati, and the A∴ A∴ (If you claim you know what the initial A's stand for in the last name, you are by definition a poseur.)

You're right: I forgot about "Kill off key characters because you've created an insanely complicated plot and aren't quite sure how to end it and/or because it's one less storyline you need to complete."